Bump v0.38.1.

* Remove obsolete mention of the custom widget placeholder prop.
* Fix HiddenWidget error when value is undefined (#277)
* Fix SchemaField to support customized DescriptionField (#292)
* Ensure arrays of numbers are properly propagated to formData (#298)
* Fix #300: Properly reset a date widget value. (#303)

package.json

@@ -1,6 +1,6 @@
 {
   "name": "react-jsonschema-form",
-  "version": "0.38.0",
+  "version": "0.38.1",
   "description": "A simple React component capable of building HTML forms out of a JSON schema.",
   "scripts": {
     "build:readme": "toctoc README.md -w",